Vocal samples / Where from?

I bought the Vengeance Vol.1 pack, but it doesnt really fill my needs as such. Im not really sure what my needs are, but I know thats not it.

I was wondering, where do producers such as Maya Jane Cole get their samples from, for example from "What They Say". Without getting some one in to the studio and singing?

Maybe you'll find something like that on loopmasters.com in their chillout area. As you can prelisten some demo tracks before buying you'll be able to judge yourself if it's what you've been searching for ;)

I personally look on youtube for an accapella version of a song..